diff --git a/src/Extension/AAC.h b/src/Extension/AAC.h
index 6c8bca5d..156c4122 100644
--- a/src/Extension/AAC.h
+++ b/src/Extension/AAC.h
@@ -156,10 +156,10 @@ public:
      * @param aac_cfg aac两个字节的配置信息
      */
     AACTrack(const string &aac_cfg){
-        if(aac_cfg.size() != 2){
-            throw std::invalid_argument("adts配置必须为2个字节");
+        if(aac_cfg.size() < 2){
+            throw std::invalid_argument("adts配置必须最少2个字节");
         }
-        _cfg = aac_cfg;
+        _cfg = aac_cfg.substr(0,2);
         onReady();
     }